Effect of renal denervation, furosemide, and acute saline loading on postobstructive diuresis in the rat

The effect of acute or chronic renal denervation, furosemide, or acute saline loading on the postobstructive diuresis (POD) which occurs after relief of 24-h bilateral ureteral obstruction (BUO) was studied in anaesthetized rats. Acute renal denervation during POD 1--2 h after relief of BUO had no effect on glomerular filtration rate of sodium, potassium, water, or solute excretion, in contrast with its natriuretic and diuretic effect in sham-operated rats. Intravenous furosemide or acute saline loading caused a further marked increase in sodium and water excretion during POD, demonstrating the ability of the kidney undergoing POD to respond to other types of natriuretic stimuli. Chronic renal denervation prior to BUO had no effect on subsequent POD. The lack of response of the BUO kidney undergoing POD to acute denervation contrasts with the changes in renal function following denervation of the unilateral postobstructive kidney. The results indicate that the kidney undergoing POD after relief of BUO may be functionally denervated and suggest that inhibition of renal nerve activity could contribute to the pathophysiology of POD.